shaders help

First I must apologize for this newbie question, but I’m trying to pass
thru an OpenGL patch for a multitouch interface, using several
jit.gl.slab objects. I would have 2 questions :

– globally : is it possible to find a general documentation about the
shaders, explaining their functions and the role of their parameters,

– particularily : I’m searchin the shader equivalent of a single
"jit.op @op >". I tried op.ceil.jxs, op.floor.jxs and several others,
but I don’t know if I misuse the parameters or if they simply aren’t
the right ones.

> – globally : is it possible to find a general documentation about the
> shaders, explaining their functions and the role of their parameters,

Nothing more than the general tutorials and the example files.

> – particularily : I’m searchin the shader equivalent of a single
> "jit.op @op >". I tried op.ceil.jxs, op.floor.jxs and several others,
> but I don’t know if I misuse the parameters or if they simply aren’t
> the right ones.

op.gt.jxs (greater than)

Please post questions like this to the *standard* Jitter mailing
list, since it’s not a C object development question.